Various techniques are used for illegitimately accessing, analyzing or extracting information from secure electronic circuitry, such as cryptographic circuitry. Some attacks, referred to as fault injection, typically involve causing a fault in the circuit, e.g., by physically contacting or damaging signal lines, by applying high-power laser or electromagnetic pulses, or by causing glitches on power supply or other external interfaces. The fault is expected to cause the circuit to output sensitive information, or otherwise assist the attacker in penetrating the circuit or the information it stores.